The monthly index of orders in value received by industry is calculated as a Laspeyres index by aggregating the elementary indices with fixed weightings.

As a value index, it theoretically has no base and simply has a reference period. Since January 2009, however, it has had a base and reference of 100 for the year 2005.

The series are adjusted for seasonal variations (CVS) and calendar or "working days" effects (CJO) in order to render the monthly index variations more easily interpretable.

Due to the year-on-year variations in the composition of years in terms of working days (presence of leap years, positioning in the week of different public holidays, etc.), the annual mean of the CVS-CJO indices may differ slightly from that of the gross indices.